1. Field
One or more embodiments of the present invention relate to an array speaker system and a method for implementing the same, and more particularly, to an array speaker system and a method for implementing the same, the system and method providing a personal sound zone for transmitting concentrated sound to a user without distortion of sound quality by canceling non-uniform radiation patterns.
2. Description of the Related Art
Array speakers are used to adjust the direction of sound to be reproduced by combining a plurality of speakers or to transmit sound to a specific zone. In order to adjust sound at a desired location or in a desired direction, an array including a plurality of sound source signals is needed. According to the principle for transmitting sound generally referred to as directivity, the plurality of sound signals are overlapped using a phase difference between the plurality of sound source signals so that intensities of the sound source signals are increased in a predetermined direction and the sound source signals are transmitted in the predetermined direction. Thus, such directivity is achieved by adjusting phases of the sound source signals output to a plurality of speakers disposed according to a predetermined location. Sound can be focused at the location of a specific listener using such directivity principle. A region in which a sound field is formed due to focusing is referred to as a personal sound zone.
Hereinafter, a sound source is a source from which sound is radiated and output and is used as the term that means an individual speaker that is an element for an array speaker. A sound field is a virtual region in which sound radiated from the sound source is formed. Hereinafter, sound field will be used to refer to a region affected by sound energy. In addition, the term sound pressure refers to a force of sound energy using the physical quantity of pressure.
When sound source signals are output to an array speaker, interference of sound source signals radiated from each speaker is not sufficient at a location within a predetermined distance from the array speaker so that a non-uniform radiation characteristic occurs. This is because sound radiated from a plurality of speakers does not form a desired sound field due to insufficient interference of radiated separate sound source signals at a short distance away from the array speaker. Such phenomenon is referred to as a near field effect. Further, when a sound field radiated from the array speaker is represented as visual patterns, the near field effect is shown as non-uniform radiation patterns.